lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Thu, 21 Dec 2017 15:32:14 +0100
From:   Paolo Bonzini <>
To:     Vitaly Kuznetsov <>
        Radim Krčmář <>,
        "K. Y. Srinivasan" <>,
        Haiyang Zhang <>,
        Stephen Hemminger <>,
        "Michael Kelley (EOSG)" <>,
        Mohammed Gamal <>,
        Cathy Avery <>, Bandan Das <>,
        Roman Kagan <>,,
Subject: Re: [PATCH RFC 0/7] KVM: nVMX: enlightened VMCS initial

On 21/12/2017 13:50, Vitaly Kuznetsov wrote:
> I'm back with (somewhat frustrating) results (E5-2603):

v4 (that would be Broadwell)?

> 1) Windows on Hyper-V (no nesting): 1350 cycles
> 2) Windows on Hyper-V on Hyper-V: 8600
> 3) Windows on KVM (no nesting): 1150  cycles
> 4) Windows on Hyper-V on KVM (no enlightened VMCS): 18200
> 5) Windows on Hyper-V on KVM (enlightened VMCS): 17100

What version were you using for KVM?  There are quite a few nested virt
optimizations in kvm/queue (which may make enlightened VMCS both more or
less efficient).

In particular, with latest kvm/queue you could try tracing vmread and
vmwrite vmexits, and see if you get any.  If you do, that might be an
easy few hundred cycles savings.


Powered by blists - more mailing lists